The new guns and ammunition the Army just married and is expected to issue to combat arms units within the next decade will require soldiers to carry an even heavier load.
But information on how those weapons should outperform the guns they're replacing -- the justification for troops to shoulder extra weight on top of mountains of gear already injuring soldiers -- is classified.
In April, the Army announced that Sig Sauer will produce replacements for the M4 rifle and M249 Squad Automatic Weapon, or SAW, starting with a trial run of about 40 new guns late next year. Production is expected to ramp up when the Army opens a new ammo plant to produce the new 6.8mm rounds for those weapons around 2026.
Army officials have touted that the new XM5, the M4's replacement, and XM250, set to replace the SAW, pack a much harder punch and will improve the combat performance of ground troops. But thus far, the service has declined to disclose evidence that those weapons outperform the M4 and SAW, including how far they can shoot accurately. And it's unclear whether the Army has verified the ranges at which those new weapons can engage an enemy before committing to a multimillion-dollar contract.
"During the prototyping phase of the program, the [weapons] demonstrated the ability to significantly outperform the M4A1 and M249 with lethal effects at all ranges," Lt. Col. Brandon Kelley said in a statement. "Following production qualification testing and operational testing, the Army will establish and validate the maximum effective ranges."
Prototyping and the Army's selection of which vendor would supply its new weapons took only 27 months. For comparison, the service spent more than a decade developing its new fitness test.
A spokesperson for Sig Sauer declined to comment, directing Military.com to the Defense Department regarding questions on its weapons.
Information on the maximum distances other Army weapons can engage targets is no secret; it's one of the first things a new recruit learns and is easily searchable online. According to Kelley, the new weapons' capabilities eventually will be disclosed, but there is no clear timetable.
The M4, the Army's current standard-issue rifle used in the post-9/11 wars, can effectively engage targets at 500 meters. The SAW can suppress targets at around 800 meters.
For comparison, the standard-issue rifle for the Chinese military is the QBZ-95, which has a maximum effective range of 400 meters for a target.
Those distances are critical for troops to be able to confront an enemy force accurately, and anything less could alter U.S. soldiers' effectiveness and even require changes to tactics. An Army report in 2009 on U.S. troops' performance in ground combat in Afghanistan found that the average gunfight was well beyond 300 meters and that any training or equipment not built for at least 500 meters would be "inappropriate."
But holding those details close to the chest before weapons are distributed to the force might be done out of fear of the Chinese government getting a sneak peek at the new guns.
"You don't want the Chinese getting it," Kelley told Military.com. "They steal tech all the time. Let's get ahead while we can."
The plan is for the new weapons to be issued only to troops in combat arms units, such as infantrymen and cavalry scouts. The Army plans to buy 107,000 XM5s and 13,000 XM250s for active-duty soldiers and National Guardsmen. But that total purchase could take the rest of the decade. Eventually, the XM5 will be renamed the M5, and the XM250 will be designated the M250.
Yet when soldiers eventually get those new guns, they will carry significantly less ammunition, given the 6.8mm is much heavier than the 5.56mm rounds the M4 and SAW use. The idea is those heavier rounds will be more effective against body armor and light vehicles. However, the Army has not disclosed any evidence on that being the case.
The XM5 weighs 8.38 pounds, or 9.84 pounds with the suppressor, much heavier than the 6.34-pound M4. That new rifle will also use 20-round magazines, smaller than the 30-round magazines troops currently use. A soldier's basic combat load will be seven of those 20-round magazines, a total of 140 rounds, weighing 9.8 pounds altogether.
The M4's combat load, also seven magazines for a total of 210 rounds, is 7.4 pounds. In total, a rifleman with the XM5 will carry roughly four pounds more than today's M4 rifleman.
"Hopefully, these are worth the bang for the buck," one Army infantry sergeant major told Military.com on the condition of anonymity because they were not authorized to talk to the press on the subject. "Asking [soldiers] to carry anything more than they already do, and having less ammo, that is a hard pitch."
How ground troops pack is meticulously planned, with even an extra single ounce taken into account as their total load has ballooned in recent decades. Soldiers often carry between 30 and 80 pounds, or possibly more depending on the mission, lugging around batteries, radios, water, food, protective gear and grenades.
"Soldiers will carry less ammunition, but the performance of that ammunition provides an increase in lethality, accuracy and range across a broader range of targets," Kelley added in a statement.
The XM250, however, weighs less, at 14.5 pounds, than the SAW, which weighs 19.2 pounds. That XM250 weight includes its bipod and suppressor.
But like the new rifle, light machine gunners will still carry that heavier 6.8mm ammo, and less of it. That could be a challenge, given a SAW gunner's job is to fire a lot of rounds, quickly, to suppress enemy movement.
A soldier with an XM250 will carry a basic load of four 100-round pouches of ammo, weighing 27.1 pounds. SAW gunners carry three, 200-round pouches, weighing 20.8 pounds.
In total, future light machine gunners will carry 200 fewer rounds of ammunition and about one extra pound when accounting for the weapon and its ammo. It is unclear what the spare barrels for the XM250 weigh.
-- Steve Beynon can be reached at Steve.Beynon@military.com. Follow him on Twitter @StevenBeynon.